New Recording Device

Radio Record, Volume IV, Issue 35, 13 March 1931, Page 15

New Recording Device

German Invention. NEW process for the refording ~~ and reproduction of sound vibra~ tions has been devised by a German inventor. It is in many respects similar to the telegraphone, in which recording was carried out by imparting varying degrees of magnetism to a steel wire as it passed between the poles of a magnetic system. Whereas in the telegraphone the variable magnetism of the steel wire is used to record and reproduce, the sound in this new method is first converted into fluctuations of light. Photographic emulsions containing metals such as silver, chromium, platinum, ete. are used exclusively, the earrier being a band of celluloid film, metal, paper, or fabric, in the form of tape, strings, or wires. The amount of metal left at the various places on this carrier will be larger where the light has been. more intense. If such a carrier is made to pass through (or close-to) a coil situated in the magnetic field of another coil, fluctuations will be set up in this second coil’ corresponding to the amount of metal at the various points of the carrier-band or string. These ‘current fluctuations will affect any suitable instrument inserted into the circuit of the second. coil. In a telephone receiver a reproduction of the original speech or music would be heard. Any amplifier of the type used in radio practice could be used

ts increase the power of the fluctua tions. This process of reproduction ean -be used either in connection with a moving picture or as a substitute-. for gramophones, = ------el